Yarn heating tube and method

ABSTRACT

A FLUID PERMEABLE CONDUIT IS POSITIONED WITHIN A SECOND CONDUIT AND SEPARATED THEREFROM BY HELICALLY INCLINED VANE MEMBERS, FORMING TWO SEPARATE HELICALLY SHAPED FLUID PASSAGEWAYS. A HEATING FLUID IS INTRODUCED INTO ONE PASSAGEWAY UNDER ELEVATED PRESSURE, WHILE THE PRESSURE IN THE OTHER PASSAGEWAY IS REDUCED. THE YARN TO BE HEATED PASSED THROUGH THE FLUID PERMEABLE CONDUIT.

1971 H. VAN DOORNEWAARD 3,555,639

YARN HEATING TUBE AND METHOD Filed March 5, 1969 23 25 27 H I I 8 ls 29J II o 9 m ///3 y //fi- |4@ 28 Y I6 l5 INVENTOR. HANS VAN DOORNEWAARD BYr A TTORNEVS United States Patent 3,555,639 YARN HEATING TUBE AND METHODHans van Doornewaard, Greenville, S.C., assignor to Phillips FibersCorporation, a corporation of Delaware Filed Mar. 3, 1969, Ser. No.803,849 Int. Cl. D02j 13/00 US. Cl. 28-62 9 Claims ABSTRACT OF THEDISCLOSURE This invention relates to method and apparatus for heatingyarn.

In conventional yarn heating tubes, air enters the tube with the yarnand moves through the tube either concurrently or countercurrently withthe yarn, while the Wall of the tube indirectly heats the yarn. Thepresence of the air in the yarn seriously reduces the heating capacityof the device, while the passage of the air from one end of the tube tothe other carries condensation and other contaminants from one sectionof the yarn to another section.

It has now been discovered that these difliculties can be avoided bysubjecting one side of each axial segment of yarn in an elongated zonewith a heating fluid while reducing the pressure on the opposite side ofeach axial segment, and continuously varying the direction of theresulting dilferential pressure with respect to the axis of the yarn aseach segment of yarn passes through the zone. This can be accomplishedby the use of a fluid permeable conduit surrounded by a second conduitand connected thereto by helical vanes to form two spiralingpassageways. A heating fluid can be supplied to one passageway atelevated pressure, while the pressure in the other passageway isreduced.

Accordingly, it is an object of the invention to provide an improvedmethod and apparatus for heating yarn. Another object of the inventionis to rapidly remove contaminants from a yarn. Another object of theinvention is to increase the heat transfer rate in a yarn heatingdevice. Yet another object of the invention is to increase the yarnthroughput for a yarn heating device.

Other objects, aspects and advantages of the invention will be apparentfrom a study of the specification, the drawing and the appended claimsto the invention.

In the drawings, FIG. 1 is an elevational view in cross section of ayarn heating device in accordance with a presently preferred embodimentof the invention, and FIG. 2 is a cross-sectional view along line k2 ofFIG. 1.

Referring now to the drawings in detail, heating device 10 comprises atubular conduit 11 positioned within larger tubular conduit 12 andextending generally parallel thereto, preferably coaxially therewith. Anannular closure plate 13 extends from one end of conduit 12 to the outerwall of conduit 11 to close the opening therebetween. Similarly, anannular closure plate 14 extends from the other end of conduit 12 to theouter wall of conduit 11 to close the opening therebetween, therebydefining an enclosed annular chamber. Helically inclined vane members 15and 16 are positioned in the annular chamber and are axially spacedapart from each other. Vane members 15 and 16 extend axially fromclosure plate 13 to closure plate 14 and laterally from the outer wallof conduit 11 Patented Jan. 19, 1971 to the inner wall of conduit 12, toform two separate helically shaped fluid passageways 17 and 18. Conduit11 is formed of a porous material, for example a sintered metal, toprovide a plurality of fluid passageways in the wall thereof spacedalong the length thereof which permit fluid communication betweenpassageways 17 and 18 and the adjacent interior 31 of conduit 11.

Conduit 21 connects one end of passageway 18 to a vacuum pump 22 orother means of reducing the pressure in passageway 18 substantiallybelow the fluid pressure in the interior of conduit 11. Conduit 23connects one end of passageway 17 to a source 24 of heating fluid at apressure above the fluid pressure in the interior of conduit 11. Ifdesired an outlet conduit can be provided at the other end of passageway17 to remove unused heating fluid. Any suitable heating fluid can beemployed, but steam is presently preferred in most instances because ofits economics and heat transfer rate. In the presently preferredembodiment illustrated in the drawing, conduits 21 and 22 are positionedadjacent the yarn inlet end of conduit 11, but it is within thecontemplation of the invention for these connections to be adjacent theyarn outlet end or at an intermediate point or points. A sleeve 25 of asuitable insulating material surrounds all or a major portion of conduit12 to prevent condensation in passageway 17. Nip rolls 26 and 27 can beprovided to pass the yarn into the heating device 10. Nip rolls 28 and29 can be utilized at the outlet end of device 10 in addition to or inlieu of the utilization of nip rolls 26 and 27. Rolls 28 and 29 can bepositioned around the outlet end of conduit 11 and driven at a slowerspeed than rolls 26 and 27 which can be positioned adjacent the inlet ofconduit 11 to thereby form a stuffer crimper.

In any plane cut through the annular chamber in heating device 10perpendicularly to the axis of conduit 11, one example being illustratedin FIG. 2, steam from passageway 17 will be entering passageway 31 ofconduit 11 through approximately one half of the wall of conduit 11 andspent steam, air and any condensate will be exiting passageway 31through the other half of the wall conduit 11 into passageway 18.Substantially all of the steam transverses passageway 31 and iswithdrawn into the opposite section of passageway 18, while theremainder of the steam passes into the superadjacent or subadjacentsection of passageway 18. The direction of the steam flow acrosspassageway 31 changes along the length of passageway 31 in a spiralingfashion. The application of steam to one side of an axial segment of theyarn and the effectuation of the reduced pressure on the opposite sideof the axial segment of yarn promotes a continuous flow of fresh steamlaterally through the axial segment of yarn. The constantly changingdirection of the steam flow which the axial segment of yarn experiencesas it travels through passageway 31 eliminates stagnant areas or eddieswithin the yarn, thereby continuously exposing all of the yarn to freshsteam, and prevents the yarn from being packed against one wall ofpassageway 31.

The reduced pressure in passageway 18 maintains the transverse flowrather than permitting the heating fluid to pass the length of conduit11 with the yarn 30-. The transverse motion of the heating fluid withrespect to the yarn not only continuously exposes each axial segment ofthe yarn to fresh heating fluid, but also achieves a rapid removal ofany condensate or other contaminants from the yarn. The removal of airfrom the yarn entering conduit 11 permits a greater degree of directcontact between the yarn and the heating fluid, resulting in a fasterheat transfer rate. This permits the usage of a shorter tube for a givenyarn throughput or an increased yarn throughput for a given length ofheating tube.

While conduit 11 is preferably made of sintered metal, it is possible toutilize a nonporous metal conduit which throughout the length of conduit11 or in a varying pattern, as desired. While nip rolls have beenillustrated as the yarn conveying means, other devices can be employed,for example, fluid jets. The term yarn, as used herein, includestextured or untextured filaments of natural or synthetic material, inthe form of staple or continuous filaments, or combinations thereof. Asingle continuous filament or a bundle of continuous and/ or staplefilaments can be processed in the device of the invention. The bundlecan range from two filaments of small denier per filament to a towhaving a total denier of 100,000 or more.

Reasonable variations and modifications are possible within the scope ofthe foregoing disclosure, the drawing and the appended claims to theinvention.

I claim:

1. Apparatus comprising first and second tubular conduits, said firstconduit being positioned inside said second conduit and extending atleast approximately parallel thereto, first closure means extending fromone end of said second conduit to said first conduit to close theopening therebetween, a second closure means extending from the otherend of said second conduit to said first conduit to close the openingtherebetween, first and second axially spaced apart substantiallyhelically inclined vane members extending axially from said firstclosure means to said second closure means and extending laterally fromthe outside wall of said first conduit to the inside wall of said secondconduit to form two separate substantially helically shaped fluidpassageways, said first conduit having a plurality of fluid passagewaysin the wall thereof spaced along the length thereof to provide fluidcommunication between said first and second fluid passageways and theadjacent interior of said first conduit, means 1 3. Apparatus inaccordance with claim 1 wherein said first conduit is formed of sinteredmetal.

4. Apparatus in accordance with claim 1 wherein said means for reducingthe pressure comprises a vacuum pump.

5. Apparatus in accordance with claim 1 wherein said means for passing ayarn through said first conduit comprises a pair of nip rolls mountedadjacent the inlet end of said first conduit.

6. Apparatus in accordance with claim 1 further comprising an insulatingsleeve positioned around said second conduit.

7. A process for heating yarn which comprises passing said yarn throughan elongated zone, subjecting one side of each axial segment of yarn insaid zone to a reduced fluid pressure and subjecting the opposite sideof each said axial segment of yarn in said zone to a heating fluid at anelevated pressure to establish a pressure differential across each saidaxial segment of yarn in said zone, and continuously varying thealignment of said pressure differential with respect to the axis of therespective axial segment of yarn in said zone as each axial segment ofyarn passes through said zone to thereby alternately subject eachportion of yarn to a reduced fluid pressure and to heating fluid atelevated pressure.

8. A process in accordance with claim 7 wherein said heating fluid issteam.

9. A process in accordance with claim 7 wherein said step ofcontinuously varying the alignment of said pressure difierentialcomprises varying said alignment in a helical manner along the axis ofsaid zone.

References Cited UNITED STATES PATENTS 2,435,891 2/1948 Lodge 2872.l2X2,896,060 7/1959 Serfass et al. 28-6'2X 3,380,132 4/1968. McKeW 2862XLOUIS K. RIMRODT, Primary Examiner U.S. Cl. X.R. 2872

